Pool filter and pump repair

Most common faults in the filtration system

A pool’s filtration system has three main components: circulation pump, filter and multiport valve. Any of them can fail, and when one fails, the whole system stops working correctly and the pool degrades chemically within days.

The circulation pump is the component with most faults due to intensive use. Standard 0.75 HP pumps are sized for 4-6 hours daily and last 5-8 years of normal service. Typical faults are worn bearings (excessive noise on start and run), failed start capacitor (pump hums but doesn’t start), damaged impeller from sucked grit (reduced flow despite nominal pressure), and burnt motor from thermal overload (pump just doesn’t work). For each case we evaluate repair vs replacement.

The sand filter is the second frequent fault point. Filter sand compacts and saturates over time and stops filtering properly. The typical sign is rising working pressure (over 1.5 bar means time to backwash or change). Sand change happens every 5-7 years in normal use. It’s a full-day operation: drain the filter, remove old sand (typically 80-120 kg for a standard domestic filter), vacuum the collector bed, refill with new properly graded sand, multiport valve adjustments, pressure test and start-up.

The filter’s multiport valve distributes water flow between filter, backwash, recirculate, drain and closed modes. Its internal mechanics wear over years and internal leakage starts between ports (filtered water returns to the pool dirty, incomplete backwash). Multiport valve replacement costs less than changing the whole filter and restores optimal operation.

When to replace the whole filtration unit

If the unit is over 15 years old, several components are aged simultaneously and one-off repairs become uneconomic. In those cases we recommend full unit replacement: new filter, pump and multiport valve installed in the existing housing. A new quality unit with a high-efficiency pump consumes up to 40% less electricity than old pumps, which on a year-round used pool means significant economic saving over 5-10 years. The simultaneous component change also gives full manufacturer warranty across the whole assembly and resets the durability clock.

For villas with large pools (over 60 m³) or pools with waterfalls and special hydraulic features, we recommend variable-speed pumps that auto-adjust flow by need. They consume 70% less than fixed-speed pumps for the same filtering effect. Initial investment is somewhat higher but pays back in 3-5 years of continuous use.

Salt chlorinator conversion

A much-requested upgrade on the Costa Blanca is converting a traditional chlorine pool to a salt-chlorinated one. The idea is to add common salt to the pool water and an electrolyser that converts it into chlorine continuously and automatically. Benefits: much softer water on skin and eyes, no chemical chlorine smell, no manual chlorine to add, more stable chemistry. Reasonable initial cost (1,100-1,700 euros installed for standard pools) and the investment pays back in 3-4 years through saved continuous chlorine purchase.